Medical device support system including rotational control mechanism

ABSTRACT

A medical device support system including a shaft, an extension arm, and a hub mounted to the shaft for pivotable movement of the extension arm about a rotation axis of the shaft. The hub includes a cavity including first and second contact faces, and at least one floating stop movably disposed in the cavity. The hub is pivotably mounted for a range of at least 360-degrees rotation about the rotation axis. The at least 360-degrees rotation range is based on a compound of a first rotation range and a second rotation range. The first rotation range is defined by a first movable amount of the at least one floating stop between first and second stop surfaces fixed relative to the shaft. The second rotation range is defined by a second movable amount of the at least one floating stop between the first and second contact faces of the hub.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.63/134,248, filed Jan. 6, 2021, U.S. Provisional Application No.63/134,254, filed Jan. 6, 2021, U.S. Provisional Application No.63/134,263, filed Jan. 6, 2021, which are hereby incorporated herein byreference in their entireties.

FIELD OF INVENTION

This application relates generally to a rotational control mechanism fora medical device suspension system or carry system for use in, forexample, a hospital examination room, a clinic, a surgery room or anemergency room, and more particularly to a rotational control mechanismthat simplifies rotational control of an extension arm about a shaft ofthe medical device support system and provides at least 360°(360-degrees) rotation of the extension arm about the shaft.

BACKGROUND

Medical device suspension systems or carry systems are used in healthtreatment settings such as hospital examination rooms, clinics, surgeryrooms and emergency rooms. These systems may suspend or support anyvariety of medical devices or components including surgical lights,supply consoles, patient monitors, camera detector heads, medicalinstruments, ventilator systems, suction devices, among others. Thesystems typically include a shaft or support spindle that is suspendedfrom the ceiling or mounted to a wall or stand, and one or moregenerally horizontal extension arms mounted for rotational movementabout the shaft. Each extension arm typically has a hub at its proximalend mounted to the shaft for pivotable movement about the shaft, and asupport at its distal end for supporting a medical device. The extensionarm can be rotatably adjusted about the shaft to a desired angularposition to provide appropriate access to medical devices and componentsassociated with the arm.

It is desirable to limit the rotation of the extension arm about theshaft for example to prevent collision of medical devices at the distalends of the arms, or to prevent undue strain on electrical orcommunication lines passing through the shaft and the extension arm. Inmost current support systems, the extension arm is equipped with a fixedfeature in the hub that contacts a fixed feature on the shaft thatprevents further rotation.

For rotational control mechanisms in some medical device suspensionsystems or carry systems, there remain various shortcomings, drawbacks,and disadvantages relative to certain applications. For example, in somesystems the rotational control mechanism limits rotation of theextension arm to below 360° (360-degrees), which may limit options forsome installations. Other rotational control mechanisms require multiplestacked components, which increase the volumetric footprint of themechanisms and complicates their integration into the hub of theextension arm.

Accordingly, there remains a need for further contributions in this areaof technology.

SUMMARY OF INVENTION

The application relates to a rotational control mechanism for a medicaldevice support system, in which the rotational control mechanism enablesat least 360° (360-degrees) rotation of the extension arm about theshaft, and also embodies fewer components and a smaller volumetricfootprint than heretofore attained, thus simplifying and addingefficiency to the factory assembly and field service of the medicaldevice support system.

According to one aspect of the invention, a medical device supportsystem includes a shaft, an extension arm, and at least one floatingstop. The extension arm may have a support for a medical device. A hubat a proximal end of the extension arm may be mounted to the shaft forpivotable movement of the extension arm and the hub about a rotationaxis of the shaft. The hub may have an elongated cavity including firstand second contact faces. The at least one floating stop may be movablydisposed in the elongated cavity of the hub between the first and secondcontact faces. The hub may be pivotably mounted for a range of at least360-degrees rotation about the rotation axis, wherein the at least360-degrees rotation range is based on a compound of a first rotationrange and a second rotation range, wherein the first rotation range isdefined by a first movable amount of the at least one floating stopbetween first and second stop surfaces fixed relative to the shaft, andwherein the second rotation range is defined by a second movable amountof the at least one floating stop between the first and second contactfaces of the hub.

Embodiments of the invention may include one or more of the followingadditional features separately or in any combination.

The at least one floating stop interfacing with one of the first orsecond stop surfaces of the shaft and one of the first or second contactfaces of the hub may restrict rotation of the hub about the rotationaxis beyond the at least 360-degrees rotation range.

The hub may be pivotably mounted for the at least 360-degrees rotationfrom a first stop position to a second stop position and vice versa,wherein at the first stop position, the at least one floating stopinterfaces with one of the first or second stop surfaces fixed relativeto the shaft and one of the first or second contact faces of the hub tolimit further counterclockwise rotation of the hub about the rotationaxis, and at the second stop position, the at least one floating stopinterfaces with an opposite one of the first or second stop surfaces andan opposite one of the first and second contact faces of the hub tolimit further clockwise rotation of the hub about the rotation axis.

The at least one floating stop may be sandwiched between the first stopsurface and the first contact face at the first stop position, and theat least one floating stop may be sandwiched between the second stopsurface and the second contact face at the second stop position.

The first movable amount of the at least one floating stop may bedetermined by an amount of movement of the at least one floating stoprotating at least partially about the rotation axis from a first stopposition, in which the at least one floating stop engages both the firststop surface and the first contact face, to an intermediate position, inwhich the at least one floating stop engages the second stop surface;and the second movable amount of the at least one floating stop may bedetermined by an amount of movement of the at least one floating stoprotating at least partially about the rotation axis from theintermediate position to a second stop position, in which the at leastone floating stop engages both the second stop surface and the secondcontact face.

The second stop surface may be configured to move the at least onefloating stop within the cavity from the intermediate position to thesecond stop position.

The first and second stop surfaces may be formed by opposite sides of atleast one fixed stop radially outwardly protruding from an outer surfaceof the shaft, the at least one fixed stop being non-rotatable about therotation axis.

The at least one floating stop may include a spherical ball.

The elongated cavity may be formed by radially inwardly projectingsurfaces of the hub that at least partially enclose the at least onefloating stop.

The radially inwardly projecting surfaces of the hub may form a radiallyinwardly projecting lug, and the first and second contact faces of thehub may form opposite end portion surfaces of the lug.

The first and second stop surfaces may radially overlap with the firstand second contact faces of the hub, and radially overlap with the atleast one floating stop; and the first and second contact faces mayinclude respective openings for receiving the first and/or second stopsurfaces, thereby enabling the first or second stop surface to move theat least one floating stop within the elongated cavity between the firstand second contact faces.

The first and second stop surfaces may radially overlap with oppositefirst and second engagement surfaces of the at least one floating stop;and the first and second stop surfaces and the opposite first and secondengagement surfaces of the at least one floating stop may lie in thesame plane that is perpendicular to the rotation axis.

The first movable amount may be less than 360-degrees, and the secondmovable amount may be in a range from 1-degree to less than 180-degrees.

The at least 360-degrees rotation range may be less than 540-degrees.

The first and second stop surfaces may be formed by opposite sides of afixed stop, and the shaft may include a plurality of receivers evenlyspaced about the rotation axis of the shaft for receiving the fixedstop.

The shaft may have an axial hollow and a radial aperture and the cavityof the hub may be positioned to allow passage of electrical andcommunication lines through the axial hollow, through the radialaperture, and into a longitudinally extending cavity in the extensionarm.

The hub of the extension arm may include upper and lower pivot bearingsconfigured to pivotably engage the hub with the shaft, and a radialopening positioned axially between the upper and lower pivot bearings;and the cavity of the hub may be positioned to allow passage of theelectrical and communication lines between the upper and lower pivotbearings, through the radial opening of the hub, and into thelongitudinally extending cavity in the extension arm.

According to another aspect of the invention, a medical device supportsystem includes a shaft, an extension arm, and at least one floatingstop. The extension arm may have a support for a medical device. A hubat a proximal end of the extension arm may be mounted to the shaft forpivotable movement of the extension arm and the hub about a rotationaxis of the shaft. The hub may include an elongated cavity having firstand second contact faces. The at least one floating stop may be disposedin the cavity and be movable between the first and second contact faces.First and second stop surfaces may be fixed relative to the shaft andradially extend to overlap with a rotation path of the at least onefloating stop. The hub may be pivotably mounted for a range of at least360-degrees rotation about the rotation axis from a first stop positionto a second stop position and vice versa, wherein at the first stopposition, the first stop surface engages a first engagement surface ofthe at least one floating stop and an opposite second engagement surfaceof the at least one floating stop engages the first contact face of thecavity, thereby limiting further counterclockwise rotation of the hubabout the rotation axis, and wherein at the second stop position, thesecond stop surface engages the second engagement surface of the atleast one floating stop and the opposite first engagement surface of theat least one floating stop engages the second contact face of thecavity, thereby limiting further clockwise rotation of the hub about therotation axis.

Embodiments of the invention may include one or more of the followingadditional features separately or in any combination.

The at least one floating stop may be configured to move with the hubabout the rotation axis from the first stop position to an intermediateposition between the first and second stop positions, wherein at theintermediate position the at least one floating stop engages with thesecond stop surface; and wherein the second stop surface is configuredto move the at least one floating stop within the elongated cavity fromthe intermediate position to the second stop position.

According to another aspect of the invention, there is provided a methodof rotating an extension arm about a shaft of a medical device supportsystem, the extension arm having a support for a medical device and ahub at its proximal end mounted to the shaft for pivotable movementabout a rotation axis of the shaft, the method including rotating thehub over a range of at least 360-degrees about the rotation axis,wherein the at least 360-degrees rotation range is based on a compoundof movement over a first rotation range and movement over a secondrotation range, wherein movement over the first rotation range includesmoving at least one floating stop of the hub between first and secondstop surfaces fixed relative to the shaft, and wherein movement over thesecond rotation range includes moving the at least one floating stopwith the first or second stop surface between first and second contactfaces of an elongated cavity of the hub.

The following description and the annexed drawings set forth certainillustrative embodiments of the invention. These embodiments areindicative, however, of but a few of the various ways in which theprinciples of the invention may be employed. Other objects, advantagesand novel features according to aspects of the invention will becomeapparent from the following detailed description when considered inconjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The annexed drawings, which are not necessarily to scale, show variousaspects of the invention.

FIG. 1 is a front elevational view of an exemplary medical devicesupport system in accordance with an embodiment of the invention.

FIG. 2 is a cross section view of an exemplary shaft and exemplaryextension arm hub connection of the FIG. 1 medical device supportsystem, showing an exemplary rotational control mechanism in accordancewith an embodiment of the invention.

FIG. 3 is a bottom, front, left isometric view of the FIG. 2 shaft andextension arm hub connection, including a portion of the rotationalcontrol mechanism.

FIG. 4 is a bottom, left isometric view of the shaft and extension armhub connection in FIG. 3 .

FIG. 5 is a top, rear, right isometric view of the FIG. 2 extension armhub, including a portion of the rotational control mechanism, but shownwithout the shaft.

FIG. 6 is partial cross-section, partial quarter section, and top, rear,left isometric view of the FIG. 2 shaft and extension arm hubconnection, including the rotational control mechanism.

FIG. 7 shows a top cross section view of the rotational controlmechanism of the medical device support system of FIG. 1 , showing amaximum clockwise position of the rotational control mechanism.

FIG. 8 shows a top cross section view of the rotational controlmechanism of the medical device support system of FIG. 1 , showing anintermediate rotation position of the rotational control mechanism.

FIG. 9 shows a top cross section view of the rotational controlmechanism of the medical device support system of FIG. 1 , showing amaximum counterclockwise position of the rotational control mechanism,where the rotation is at least 360-degrees rotation from that shown inFIG. 7 .

FIG. 10 shows a flowchart of a method of operating the medical devicesupport system of FIG. 1 .

FIG. 11 is a partially exploded bottom, front, left isometric view ofanother exemplary shaft and extension arm hub connection, includinganother exemplary rotational control mechanism, similarly to that shownin FIG. 3 , and further showing an assembly operation of the rotationalcontrol mechanism.

FIG. 12 shows a top cross section view of another exemplary rotationalcontrol mechanism of a medical device support, showing a maximumcounterclockwise position of the rotational control mechanism, similarlyto that shown in FIG. 9 , except with a different configuration of anexemplary floating stop.

DETAILED DESCRIPTION

While the present invention can take many different forms, for thepurpose of promoting an understanding of the principles of theinvention, reference will now be made to the embodiments illustrated inthe drawings and specific language will be used to describe the same. Itwill nevertheless be understood that no limitation of the scope of theinvention is thereby intended. Any alterations and further modificationsof the described embodiments, and any further applications of theprinciples of the invention as described herein, are contemplated aswould normally occur to one skilled in the art to which the inventionrelates.

Referring initially to FIGS. 1 and 2 , an exemplary medical devicesupport system 10 is shown. The medical device support system 10generally includes a shaft 14, at least one extension arm 16 having asupport 20 for a medical device 30, and a hub 34 at a proximal end ofthe extension arm 16 and mounted to the shaft 14 for pivotable movementabout a rotation axis A-A of the shaft 14. The medical device supportsystem 10 also includes an exemplary rotational control mechanism 40integrated into the hub 34 and which cooperates with the shaft 14 tocontrol an amount of rotation of the extension arm 16 about the shaft14.

According to an aspect of the present invention, the exemplaryrotational control mechanism 40 enables a range of at least 360°(360-degrees) rotation of the extension arm 16 about the rotation axisA-A of the shaft. More specifically, according to at least one aspect ofthe invention which is described in further detail below, the exemplaryrotational control mechanism 40 described herein includes at least onefloating stop movably disposed in an elongated cavity of the hub, andwhich interacts with first and second contact faces of the hub, and withfirst and second stop surfaces fixed relative to the shaft, forproviding the range of at least 360-degrees rotation of the extensionarm 16 about a rotation axis A-A of the shaft 14.

As shown in the illustrated embodiment, the medical device supportsystem 10 may be a suspension type carrying support system for use in ahospital examination room, a clinic, a surgery room, an emergency room,among others. The shaft 14 extends along axis A-A, which also representsthe rotation axis A-A of the shaft 14 about which the extension arm 16pivots. The shaft 14 may be fixed to a ceiling support 110 to remainstationary relative to the ceiling. It will be appreciated, of course,that the medical device support system 10 may have any suitablesuspension or carrying structure and that the shaft 14 may be attachedto a ceiling as shown, or to a wall, floor, movable cart, or acombination of the foregoing.

In exemplary embodiments, the shaft 14 of the medical device supportsystem 10 has a cylindrical shape in axial cross section and defines anaxial hollow 112 therein, and extends vertically downward from theceiling support 110. A column section 114 surrounds an upper portion ofthe shaft 14. The axial hollow 112 and the column section 114 houseupper portions of accessory and service lines such as power cables forsurgical lights and other power requirements, control wiring for controlelectronics, optical fibers for data communication, and/or tubing forirrigation, suction, etc. A plurality of extension arms 16, such asthree in the illustrative embodiment, are mounted for rotatable movementto the shaft 14 and extend laterally outward from the shaft 14. In theFIG. 1 embodiment, the extension arms 16 extend horizontally, orperpendicularly, relative to the shaft 14. An additional extension arm130, support arm 132, and medical device 134 may be pivotably mounted toa separate central shaft 136 radially offset from the central shaft 14.

As shown, the hub 34 is located at the proximal end of the extension arm16 and aids in the pivotable movement of the extension arm 16 about theshaft 14. The hub 34 may be unitary with the extension arm, or mayattached to the proximal end of the extension arm 16 in any suitablemanner. Each extension arm hub 34 may include upper and lower bearingmounts 150, 152 (as shown in FIG. 2 , for example) that house respectiveupper and lower pivot bearings mounted to the shaft 14. The bearingmounts 150, 152 enable rotational movement of the extension arm 16 andhub 34. Any suitable pivot bearings may be used to enable the relativerotational movement between the extension arm 16 and the shaft 14,including for example ball bearings, sleeve bearings, bushings, rotaryjoints, swivel joints and/or the like.

A brake assembly 160 may be secured in the hub 34 for rotation therewithto selectively increase and decrease a frictional braking force to theshaft 14. In the illustrative embodiment, the brake assembly 160 ispositioned above the lower bearing mount 152. Each hub 34 also mayprovide a radial opening 164, which may be positioned axially betweenthe upper and lower pivot bearings 150, 152, for routing accessory andservice lines from the axial hollow 112 and/or the upper column section114 to a longitudinally extending cavity 166 of the extension arm 16,and/or vice versa. Each hub 34 is also provided with an access opening168 to enable access to the shaft 14, the rotational control mechanism40, the upper and lower pivot bearings 150, 152, the brake assembly 160,accessory and service lines, and/or other components within the hub 34.A suitable brake assembly 160 and access opening 168 for theillustrative embodiment are described in U.S. patent application Ser.Nos. 16/517,703; 16/517,704; 16/517,707; and 16/517,708, which areincorporated by reference for all purposes as if fully set forth herein.

Referring now particularly to FIGS. 2-9 , the exemplary rotationalcontrol mechanism 40 will now be described in further detail. Generally,the rotational control mechanism 40 is made up of a combination ofcontact faces, or surfaces, including those from the hub 34 and theshaft 14, which interact with at least one free floating member 42 tocontrol the amount of rotation of the extension arm 16 about therotation axis A-A of the shaft 14. The rotational control mechanism 40enables the range of at least 360-degrees of rotation of the extensionarm 16 about the rotation axis A-A of the shaft 14. More specifically,according to an aspect, the exemplary rotational control mechanism 40includes the at least one floating member 42 in the form of a floatingstop (also referred to with 42) that is movably disposed in a cavity 44of the hub 34 to interact with first and second contact faces 46, 48 ofthe hub 34, and also which is configured to interact with first andsecond stop surfaces 50, 52 fixed relative to the shaft 14 for providingthe range of at least 360-degrees rotation.

The at least 360-degrees rotation range of the extension arm 16 aboutthe shaft 14 may be based upon a compound of ranges depending on themovement of the floating stop 42, and which contact faces 46, 48 or stopsurfaces 50, 52 engage the floating stop 42, as will be described infurther detail below. The compound of ranges includes at least a firstrotation range and a second rotation range. In exemplary embodiments,the first rotation range is defined by a first movable amount of the atleast one floating stop 42 between the first and second stop surfaces50, 52 fixed relative to the shaft 14, and the second rotation range isdefined by a second movable amount of the at least one floating stop 42between the first and second contact faces 46, 48 in the cavity 44 ofthe hub 34.

The cavity 44 of the hub 34 containing the at least one floating stop 42may be formed by any suitable surface or surfaces of the hub 34 that areconfigured to movably support and contain the floating stop 42, andwhich such surface(s) are configured to co-rotate along with theremainder of the hub 34. For example, the cavity 44 may be formed by atleast one radially projecting surface of the hub 34, such as a shelf orrim, that supports the floating stop 42 during movement thereof. In theillustrated embodiment, the cavity 44 is formed by a radially projectingsegment, or lug 54, of the hub 34. In exemplary embodiments, thefloating stop 42 is configured to move within the cavity 44 along acircumferential path about the axis A-A between the first and secondcontact faces 46, 48 of the hub 34 (as described in further detailbelow). As such, the cavity 44 containing the floating stop 42 may beconfigured as an elongated circumferential channel that guides thefloating stop 42 along its circumferential path.

As shown, the cavity 44 of the hub 34 containing the at least onefloating stop 42 may be located in an annular region between a radiallyouter surface 55 of the shaft 14 and a radially inner surface of the hub34. In the illustrated embodiment, for example, a radially inner surface56 of the hub 34 is radially outwardly spaced from the radially outersurface 55 of the shaft 14 to form an annular gap 57. The cavity 44 isformed by the lug 54 (or other suitable support) of the hub 34 thatprojects radially inwardly from the radially inner surface 56 of the hub34 into the annular gap 57. As shown, the lug 54 forming the cavity 44contains the floating stop 42 with a lower radially projecting wall 58and an upper radially projecting wall 59, each of which includecorresponding axially extending surfaces that together form acircumferential wall 60 that at least partially encloses the cavity 44and contains the floating stop 42. In exemplary embodiments, thecircumferential wall 60 of the lug 54 is radially spaced apart from theouter surface 55 of the shaft 14 to prevent or minimize contact and thusminimize friction.

To restrict rotational movement of the floating stop 42 about the axisA-A, and thereby control the rotation of the extension arm 16 and hub 34relative to the shaft 14, the hub 34 provides the first and secondcontact faces 46, 48 (also referred to as stop surfaces) on oppositesides of the hub cavity 44. The contact faces 46, 48 are configured toengage with the floating stop 42 when the extension arm 16 and hub 34are pivotably rotated about the shaft 14 between opposite first (FIG. 7) and second (FIG. 9 ) stop positions, which are at least 360-degreesapart, as described in further detail below. As shown in the illustratedembodiment, the first and second contact faces 46, 48 are angularly(circumferentially) spaced apart from each other along the rotationalpath of the floating stop 42 to define opposite ends of the lug 54 ofthe hub 34. The contact faces 46, 48 of the hub 34 may be provided inany suitable manner, such as being integral and unitary with the lug 54and/or other portions of the hub 34, as shown; or may be provided asdiscrete members, such as pins, screws, or the like, which are coupledto the hub 34.

As is apparent in the illustrated embodiment, the angular(circumferential) spacing between the first and second contact faces 46,48 of the hub 34 may be used to set the rotational limits of theextension arm 16 and hub 34 relative to the shaft 14 to 360-degrees, ormay be used to set the rotational limits of the extension arm 16 and hub34 relative to the shaft beyond 360-degrees. Such angular spacing androtational control also may be determined, at least in part, by theangular span (circumferential distance) between opposite sides of the atleast one floating stop 42 (or multiple floating stops) and the angularspan (circumferential distance) between the opposite first and secondcontact surfaces 50, 52 that are fixed relative to the shaft 14.Generally, the greater the angular span between contact faces 46, 48 ofthe hub 34, the greater the amount of rotation beyond 360-degrees.

The floating stop 42 may be any suitable member that is free to rotateabout the axis A-A relative to each of the hub 34 and the shaft 14, andwhich is permitted to interact with the first and second contact faces46, 48 of the hub 34, and also interact with the relatively fixed firstand second stop surfaces 50, 52 (fixed relative to the shaft 14), tothereby control rotational movement of the hub 34 relative to the shaft14. Such interaction of the floating member 42 with the contact faces46, 48 and stop surfaces 50, 52 also enables the at least 360-degrees ofrotation of the hub 34 about the shaft 14, as described in furtherdetail below.

Generally, the floating stop 42 is configured to withstand the forces(e.g., compressive forces) imparted upon it during engagement with therespective contact faces 46, 48 and/or stop surfaces 50, 52. Towithstand such forces without permanent deformation, the floating stop42 may be made of a suitable rigid material, such as a stainless steel,or rigid plastic. To minimize stress risers on the floating stop 42, thecontact faces 46, 48, and/or the stop surfaces 50, 52, such engagementinterfaces may be configured in a complimentary manner to each other toenhance contact area. In some embodiments, the floating stop 42 (or atleast one of the floating stops when multiple are used) may providedamping characteristics to the movement between stop positions. In suchembodiments, the at least one floating stop 42 may be made of a suitableelastomer, for example. In exemplary embodiments, the floating stop 42also is configured to slide along the surfaces of the hub 34 (e.g., lug54) forming the cavity 44 with minimal friction and wear. Suitableanti-friction or slip-coatings may be provided on such surfaces of thehub 34 and/or floating stop 42 to reduce friction and wear.

As shown in the illustrated embodiment, to further enhance movability ofthe floating stop 42 without binding, and to minimize friction and wear,the at least one floating stop 42 is configured as a spherical ballbearing. The surface(s) forming the elongated cavity 44 also may beformed as curved bearing race(s) for providing a suitable rollinginterface with the ball bearing (also referred to with 42). As shown inthe illustrated embodiment, for example, the internal surfaces of thelug 54 forming the cavity 44 are formed in a curved shape that iscomplimentary to the spherical shape of the ball bearing 42. The bearingrace of the lug 54 is formed in a complimentary arcuate shape thatenables the ball bearing 42 to move along its rotational, orcircumferential, path to engage the first and second contact faces 46,48 on the opposite sides of the cavity 44. As best shown in FIGS. 7-8 ,for example, the first and second contact faces 46, 48 of the hub 34also may formed in a complimentary shape to the shape of the sphericalball bearing 42 to enhance contact area when the ball bearing 42interfaces against the contact faces 46, 48.

The first and second stop surfaces 50, 52 fixed relative to the shaft 14may be provided as any suitable structure (or combination of structures)configured to interface with the at least one floating stop 42 andthereby provide interaction with the contact faces 46, 48 of the hub 34to control rotation of the extension arm 16 relative to the shaft 14. Inexemplary embodiments, the first and second stop surfaces 50, 52 arefixed in position relative to the radially outer surface 55 of the shaft14 (i.e., are non-rotatable about the axis A-A). In the illustratedembodiment, the first and second stop surfaces 50, 52 are formed byfixed stop 62 operatively coupled to the shaft 14, such that the firstand second stop surfaces 50, 52 form opposite sides of the fixed stop62. As shown, the fixed stop 62 may be a single fixed stop. The fixedstop 62 may be in the form of a pin, bar, rod, roller, or otherprotuberance coupled to the shaft 14 and which is non-rotatable aboutthe axis A-A. It is understood that more than one such fixed stop 62(e.g., pin), or other suitable structure (e.g., protuberance or recess),may be provided to form the first and second stop surfaces 50, 52, aswould be understood by those having ordinary skill in the art.

To provide engagement with the floating stop 42 when the hub 34 isrotated about the shaft 14, the first and second stop surfaces 50, 52(e.g., the fixed stop 62) are configured to radially overlap with therotational path of the floating stop 42. For example, in the illustratedembodiment where the hub 34 is disposed radially outwardly of the shaft14, the first and second stop surfaces 50, 52 radially outwardlyprotrude relative to the outer surface 55 of the shaft 14 to interactwith the floating stop 42 disposed in the cavity 44 of the hub 34. Asshown, the fixed stop 62 having the stop surfaces 50, 52 may protruderadially outwardly relative to the outer surface 55 of the shaft 14 toextend radially across at least a portion of the annular gap 57 to aposition at which a first engagement surface 66 of the floating stop 42can engage the first stop surface 50 of the fixed stop 62, and a second(opposite) engagement surface 68 of the floating stop 42 can engage thesecond stop surface 52 of the fixed stop 62, as will be described ingreater detail below. Also as shown (such as in FIG. 5 ), the lug 54 (orother hub segment) containing the floating stop 42 may include suitableopenings 63 in the contact faces 46, 48, and includes a slot 64 alongthe circumferential wall 60, to enable the fixed stop 62 (e.g., pin) tobe received within the cavity 44 to engage the floating stop 42 and movecircumferentially within the cavity 44. In this manner, and as describedin further detail below, the fixed stop 62 (e.g., pin) is received intothe opening of the cavity 44 to enable engagement with, and movement of,the floating stop 42 from one rotational end position at the firstcontact face 46 to the opposite rotational end at the second contactface 48, thereby providing rotational control and enabling the at least360-degrees of rotation. It is understood that although shown anddescribed as the fixed stop 62 extending radially across the annular gap57 to engage the floating stop 42, alternatively or additionally thefloating stop 42 could include a radially inwardly protruding portionthat extends radially across at least a portion, or the entirety, of theannular gap 57 to contact the first and second fixed stop surfaces 50,52 (fixed relative to the shaft 14), as would be understood by thosehaving ordinary skill in the art.

As shown in the illustrated embodiment, the fixed stop 62 protrudingradially outwardly relative to the shaft 14 and the floating stop 42protruding radially inwardly relative to the wall of the hub 34 lie inthe same horizontal plane that is perpendicular to the rotation axisA-A. Also shown in the illustrated embodiment, the radially inwardlyprotruding portion of the hub 34 (e.g., lug 54) and the floating stop 42lie in the same horizontal (rotational) plane with each other, and liein the same plane with the fixed stop 62, which said plane isperpendicular to the rotation axis A-A. In this way, the rotationalcontrol mechanism 40 embodies fewer components and a smaller volumetricfootprint than heretofore attained, and simplifies and adds efficiencyto the factory assembly and field service of the medical device supportsystem 10. Of course, the invention need not be limited as such andother embodiments are contemplated. For example, the radially outwardprotruding fixed stop 62 may be located in a plane axially above oraxially below the plane in which the floating stop 42 and the elongatedcavity 44 lie. In another example, the radially outward protruding fixedstop 62 may be located in a plane axially above or axially below theplane in which the floating stop 42 lies, and the elongated cavity 44may have an axial height such that the radially outward protruding fixedstop 62 and the floating stop 42, although themselves in differentplanes, both lie in the axial height plane of the elongated cavity 44.

In the illustrative rotational control mechanism 40, there is only asingle cavity 44 in a hub projection (e.g., lug 54) holding a singlefloating stop 42 (e.g., ball bearing) configured to interact with asingle fixed stop 62 (e.g., pin). It will be appreciated, however, thatmore than one elongated cavity 44, more than one floating stop 42 and/ormore than one fixed stop 62 may be suitable for the rotational controlmechanism 40. In other embodiments, there may be, two, four, etc. suchrespective components. It is furthermore noted that the number ofelongated cavities 44 need not be the same as the number of radiallyoutwardly protruding fixed stops 62.

Referring now more particularly to FIGS. 7-9 , an exemplary operation ofthe rotational control mechanism 40 will now be described in furtherdetail. As discussed above, the rotational control mechanism 40 mayenable the at least 360-degree rotation range based on a compound of afirst rotation range and a second rotation range. In the illustratedembodiment, the first rotation range is determined by the at least onefloating stop 42 being movable by a first amount between the first andsecond stop surfaces 50, 52 fixed relative to the shaft 14 (e.g.,opposite sides of the fixed stop 62, or pin 62) due to rotationalmovement of the hub 34 relative to the shaft 14. In the illustratedembodiment, the second rotation range is determined by the at least onefloating stop 42 being movable by a second amount within the elongatedcavity 44 between the first and second contact faces 46, 48 of the hub34 due to forces imparted by engagement with the stop surface(s) 50, 52(e.g., sides of the pin 62). In this manner, the hub 34 is pivotablymounted for a range of at least 360-degrees rotation about the rotationaxis A-A from a first stop position to a second stop position and viceversa.

The exemplary operation will be shown and described in even furtherdetail, starting with reference to FIG. 7 and comparing this to FIG. 8 .In FIG. 7 , the illustrative rotational control mechanism 40 is shown inits first stop position. As shown, in the first stop position, the firststop surface 50 (e.g., first side of the pin 62) engages a firstengagement surface 66 of the floating stop 42. The floating stop 42 issandwiched between the first stop surface 50 (e.g., pin) and the firstcontact face 46 of the hub 34, such that a second (opposite) engagementsurface 68 of the floating stop 42 engages the first contact face 46. Asis apparent in the illustrated state of FIG. 7 , the ability to furtherrotate the hub 34 clockwise about the axis A-A is restricted. However,in the illustrated state of FIG. 7 , the hub 34 is free to rotate aboutthe axis A-A in a counterclockwise direction, as shown with comparativereference to FIG. 8 .

FIG. 8 shows an intermediate rotational state in which the hub 34 hasbeen rotated counterclockwise about the axis A-A of the shaft 14 byabout 180-degrees relative to the first stop position shown in FIG. 7 .As shown, assuming that the floating stop 42 remains idle or stationarywith respect to rotation of the hub 34, the floating stop 42 isco-rotated along with the hub 34 to the intermediate position. In theillustrated state, for example, the floating stop 42 is less than180-degrees from contacting the second stop surface 52 (e.g., secondside of pin 62). As the hub 34 continues its rotation in thecounterclockwise direction, the floating stop 42 will continue to becarried along with the hub 34 in the counterclockwise direction. It isunderstood that by virtue of forces (e.g., inertia) and/or frictioncoefficient, the floating stop 42 may move or shift within the cavity 44during rotation of the hub 34, such that the floating stop 42 (e.g.,ball) does not remain exactly in the same position during rotationalmovement of the hub 34. It also is understood that the hub 34 may berotated back in the clockwise direction from the intermediate position,or any other position between its first and second stop positions, asmay be desired during use of the medical device.

Although not expressly shown in the illustrated states, it is understoodby comparing the intermediate position in FIG. 8 to the second stopposition in FIG. 9 , that the first rotation range of the rotationalcontrol mechanism is achieved when the floating stop 42 moves about theaxis A-A with the hub 34 from the first stop surface 50 (e.g., the firstside of the pin 62) to engagement with the second stop surface 52 (e.g.,the second, opposite side of the pin 62). In the illustration, it isassumed that the second engagement surface 68 of the floating stop 42remains in its position relative to the hub 34 during rotation, i.e., inengagement with the first contact face 46 of the hub 34.

With the foregoing intermediate state in mind, and with comparativereference to FIG. 9 , in the illustrated embodiment the second rotationrange begins when the second engagement surface 68 of the floating stop42 engages with the second stop surface 52 (e.g., second side of pin 62)and ends when the opposite engagement surface 66 of the floating stop 42engages with the second contact face 48 of the hub 34. Within thissecond rotation range, the fixed stop 62 (e.g., pin) is configured toenter into the cavity 44 via the opening 63 in the first contact face 46of the hub 34, and engage with and apply force to move the floating stop42 within the cavity 44. Because the floating stop 42 may beunconstrained from movement in its circumferential path in the cavity42, the fixed stop 62 (e.g., pin) moves along the slot 64 in thecircumferential wall 60, and continues to apply force to move thefloating stop 42 until the floating stop 42 engages the second contactface 48 of the hub 34. At the second stop position (shown in FIG. 9 ),the at least one floating stop 42 is sandwiched between the second stopsurface 52 (e.g., pin 62) and the second contact face 48 of the hub 34,restricting further counterclockwise rotation of the hub 34 relative tothe axis.

It is apparent from the foregoing exemplary operation that the sameprocess, but in reverse, can be applied for clockwise rotation of thearm 16 and hub 34 relative to the shaft 14 and axis A-A to providecorresponding first and second rotation ranges to achieve the at least360-degrees in the opposite direction.

As will be appreciated, in the illustrated embodiment where the floatingstop 42 is configured as a ball 42, for example, the second engagementsurface 68 of the ball 42 that engages with the first contact face 46 ofthe hub 34 may roll as the ball 42 moves within the cavity 44, such thatthis same engagement surface 68 may engage with the second contact face48 of the hub 34. Thus, reference to the “first” and “second” engagementsurfaces 66, 68 of the floating stop 42 refers to those engagementsurfaces in a state when interfacing against an opposing surface,understanding that it can be the same surface of the floating stop 42making such contact by virtue of the movement (e.g., rolling) in thecavity 44. Similarly, if the fixed stop 62 is configured as a rollerthat rotates about its own axis but does not rotate about the axis A-A,then such roller may have first and second stop surfaces 50, 52 inengagement with the floating stop 42, which these “first” and “second”stop surfaces may be the same depending on the rolling position of theroller (fixed stop 62).

Also as will be appreciated, in operation, the first and second rotationranges might not be completed in serial fashion but rather may becompleted at least partially in parallel fashion. For example, it willbe appreciated that the first movement amount of the floating stop 42between the first and second stop surfaces 50, 52 (e.g., opposite sidesof the pin 62), and the second movement amount of the floating stop 42between the first and second contact faces 46, 48 on opposite sides ofthe cavity 44, may vary depending on the forces and/or friction betweenthe respective rotating and/or sliding surfaces of these components.Thus, while FIG. 7 shows the start of the first and second rotationranges, and FIG. 9 shows the completion of the first and second rotationranges, what occurs between the start and completion of the first andsecond rotation ranges may depend on the friction and/or forces (e.g.,inertial forces) between the rotating and/or sliding surfaces.

It will be appreciated that the rotational control mechanism 40 canprovide a rotation range greater than 360-degrees, or a rotation rangeequal to 360-degrees, or even a rotation range less than 360-degrees, byadjusting any of its components, for example the width (angular span) ofthe elongated cavity 44, and more particularly the width (angular span)between contact faces 46, 48; the width (angular span) between the firstand second stop surfaces 50, 52 (e.g., opposite faces of the at leastone fixed stop 62); and/or the width (angular span) between the oppositeengagement surfaces 66, 68 of the floating stop 42.

In the illustrated embodiment, for example, the angular span between thefirst and second contact faces 46, 48 of the hub defining the elongatedcavity 44 is about 45-degrees. The floating stop 42 (e.g., ball) has anangular span of about 13-degrees. The fixed stop 62 has an angular spanof about 5-degrees. Thus, and assuming a negligible thickness at theopposite ends of the cavity 44 at the first and second contact faces 46,48, the first rotation range is about 342-degrees (360 minus 13 minus5), and the second rotation range (e.g., from the floating stop 42 firstcontacting the fixed stop 62 to then engaging the second contact face 48of the hub 34) is about 32-degrees (45 minus 13). An example of thebeginning of the first and second rotation ranges is shown in FIG. 7 andthe end of the first and second rotation ranges is shown in FIG. 9 . Asshown in FIG. 7 , a transverse axis B-B of the extension arm 16perpendicular to the rotation axis A-A is at a first angular positionwith an angular offset α relative to a transverse axis C-C of the fixedstop 62 (e.g., pin), which this angle α is about 7-degrees clockwisefrom the transverse axis C-C in the illustrated embodiment. Comparingthis to FIG. 9 , where the extension arm 16 and hub 34 have rotatedabout the shaft 14 and axis A-A in a counterclockwise direction (thatis, the extension arm 16 and hub 34 have rotated the first and secondrotation ranges), the extension arm 16 (axis B-B) rotatescounterclockwise from the angular position of FIG. 7 (that is, theposition that is 7-degrees clockwise from the transverse axis C-C of thefixed stop 62) toward the transverse axis C-C, then 360-degrees, andthen beyond the transverse axis C-C of the fixed stop 62 to a secondangular position where the transverse axis B-B of the extension arm 16is at an angular offset α′ relative to the transverse axis C-C of thefixed stop 62, which this angle α′ is about 7-degrees counterclockwisefrom the transverse axis C-C in the illustrated embodiment. Thus, in theillustrated embodiment, the extension arm 16 and hub 34 are rotatableabout the shaft 14 and axis A-A by about 374-degrees (the first rotationrange of 342-degrees plus the second rotation range of 32-degrees).

As will be appreciated, the minimum range of total rotation of theextension arm 16 and hub 34 about the shaft 14 and axis A-A may be360-degrees or greater than 360-degrees, or even up to just less than720-degrees (e.g. 710-degrees) if the angular spans of the floating stop42, cavity 44, and fixed stop 62 components so permit. As noted above,this total rotation range may be a compound of the first and secondrotation ranges. Where the floating stop 42 is in engagement with thefirst contact face 46 when the floating stop engages the second stopsurface 52, the arm will have rotated the maximum of the first rotationrange and a minimum or none of the second rotation range. Likewise,where the floating stop 42 is in engagement with the second contact face48 when the floating stop engages the second stop surface 52, then thearm will have rotated the maximum of the first rotation range and themaximum of the second rotation range, such as shown in FIG. 9 .Similarly, where the floating stop 42 is not in engagement with eithercontact face 46 or 48, then the arm will have rotated in the middle ofthe second rotation range. Generally, each of the first and secondrotation ranges enable greater than 0-degrees of rotation to enable theat least 360-degrees of rotation of the extension arm 16 about the shaft14. It is of course further understood that the rotational controlmechanism 40 may be modified to provide less than 360-degree totalrotation, such as by increasing the angular spans of the floating stop42 and/or fixed stop 62; or adding additional fixed stops 62.

In exemplary embodiments, the elongated cavity 44 forms an arcuatesegment defined by an angular span between the opposite first and secondcontact faces 46, 48 that may be in a range from about 1-degree to about180-degrees, and even more particularly from about 10-degrees to about60-degrees, such as about 45-degrees in the illustrated embodiment. Inexemplary embodiments, the angular span between the first and secondstop surfaces 50, 52 (e.g., width of fixed stop 62) may be in a rangefrom about 1-degree to about 45-degrees, even more particularly between1-degree and 20-degrees, such as about 5-degrees in the illustratedembodiment. In exemplary embodiments, the floating stop 42 may have anangular span in a range from about 1-degree to about 45-degrees, evenmore particularly between 1-degree and 20-degrees, such as about13-degrees in the illustrated embodiment. In exemplary embodiments, theat least 360-degrees range provided by the rotational control mechanism40 may be in a range from 360-degrees to less than 720-degrees, moreparticularly from 360-degrees to 540-degrees, and even more particularlyfrom 360-degrees to 450-degrees, such as about 374-degrees in theillustrated embodiment.

Referring now to FIG. 10 , there is shown a flowchart 200 of theexemplary method of rotating an extension arm about a shaft of a medicaldevice support system, such as for the medical device support system 10shown in FIG. 1 . The method includes at step 210 rotating a hub of theshaft over a range of at least 360-degrees about a rotation axis of theshaft, wherein the rotation range is based on a compound of movementover a first rotation range and movement over a second rotation range.At step 220, the method includes moving the hub the first rotation rangeincluding moving a floating stop between first and second stop surfacesfixed relative to the shaft. At step 230, the method includes moving thehub the second rotation range including moving the floating stop betweenfirst and second contact faces of a cavity of the hub.

Turning to FIG. 11 , an exemplary method of assembling a medical devicesupport system 10, and more particularly a rotational control mechanism40, is shown. The medical device support system 10 and the rotationalcontrol mechanism 40 is substantially the same as that described abovein connection with FIGS. 1-9 , except that the portions of the hub 34defining the elongated cavity 44 are illustrated as a multi-partassembly structure for facilitating assembly and/or maintenance of thesystem 10. Consequently, the same reference numerals are used to denotestructures corresponding to the same or substantially similar structuresbetween the system shown in FIG. 11 and the system shown in FIG. 1 .Moreover, the foregoing description of the system 10 in FIGS. 1-9 isequally applicable to the system 10 in FIG. 11 , except as noted below.

As shown in the illustrated embodiment, the lower wall 58 for formingthe elongated cavity 44 and supporting the floating stop 42 (e.g., ball)is couplable to another portion of the hub 34 via suitable fasteners,such as screws 70, which are received in suitable receivers 72 in thelower wall 58 (e.g., through bores) and in receivers 73 in the receivingportion of the hub 34 (e.g., threaded bores). This enables ease ofassembly for enclosing the floating stop 42 within the cavity 44, andalso may enable improved maintenance, such as for lubricating surfacesin the cavity and/or replacing the floating stop 42 due to wear. It isunderstood, however, that other assembly methods may be employed. Forexample, in the illustrative embodiment of FIG. 1 , the cavity 44 may beformed by a unitary surfaces of the hub 34, such as by additivemanufacturing, in which the floating stop 42 is additively manufacturedand enclosed within the cavity 44 during the additive manufacturingprocess. Alternatively, a window or other access opening could beemployed for placing the floating stop 42 (e.g., ball) within the cavity44. Generally, as would be understood by those having ordinary skill inthe art, one or more portions of the hub 34 forming the cavity 44 may beunitary with other portions of the hub 34; or one or more surfacessupporting and/or containing the floating stop 42 may be operativelyattached to portions of the hub 34 in any suitable manner.

Similarly to the system 10 described above in connection with FIGS. 1-9, the system 10 shown in FIG. 11 includes a plurality of angularly(circumferentially) spaced apart receivers 74 in the shaft 14, such asbore holes, that are configured to receive the fixed stop 62 (e.g.,pin). Any suitable number of receivers 74 in any suitable configurationmay be provided for securing the fixed stop 62, eitherremovably/adjustably or non-removably/non-adjustably, relative to theshaft 14. This enables greater flexibility in the design of system 10.For example, where the system 10 is installed in a particular positionwithin the room, such as near a corner or near other equipment, theability to selectively decide the rotational path of the extension arm16 during assembly provides greater flexibility during the assemblyprocess. Moreover, the ability to adjust such rotational positions byadjusting the location of the fixed stop 62 about the shaft 14 enablesimproved flexibility, such as when the room layout is modified, withouthaving to relocate the entire system 10. Moreover, the multiplelocations of the receivers 74 also may enable multiple fixed stops 62 tobe employed in the system 10, such as where less than the fullrotational range enabled by the rotational control mechanism 40 isdesired, such as for limiting the rotational travel to only 360-degrees,or even less than 360-degrees. Such possibilities greatly enhance theflexibility the system design.

Briefly turning back to FIG. 7 , for example, twelve such receivers 74are provided in evenly spaced apart positions (e.g., 30-degrees apart)about the shaft 14 for receiving the fixed stop 62. In the illustratedembodiment, the receivers 74 are configured as counter-sunk threadedbores in which the fixed stop 62 (e.g., threaded pin) may be threadedinto the threaded bore. Alternatively, the bores may be through holesand the fixed stop may be press fit into the bores. In either case, theposition of the fixed stop(s) 62 are removable and selectivelyadjustable to control the rotational movement of the extension arm 16and hub 34 relative to the shaft 14.

Again referring to FIG. 11 , and similarly to the system 10 in FIGS. 1-9, to facilitate assembly and/or adjustment of the rotational controlmechanism 40, the hub 34 includes opening 168, such as a window, whichmay be covered by a suitable cover (not shown) and fastened withsuitable fasteners, such as screws 75. As shown, the hub 34 also mayinclude at least one notched portion 76, or cutout, for facilitatinginsertion and/or removal of the fixed stop 62 during assembly and/oradjustment of the rotational control mechanism 40. The notchedportion(s) 76 are circumferentially offset from the cavity 44, andaxially align with the location of the receivers 74 in the shaft 14.This is because, in the illustrated embodiment, the hub 34 generally maybe axially constrained once installed on the shaft 14.

Turning now to FIG. 12 , another exemplary embodiment of a medicaldevice support system 310 including an exemplary rotational controlmechanism 340 is shown. The system 310 and rotational control mechanism340 is substantially the same as the above-referenced medical devicesupport system 10 and rotational control mechanism 40, except that thefloating stop 342 in the illustrated embodiment of FIG. 12 is configuredin a polyhedron shape and surfaces of the hub 334 and/or fixed stop 362are configured complimentary to the floating stop 342. Consequently, thesame reference numerals but indexed by 300 are used to denote structurescorresponding to similar structures in the systems 10, 310. In addition,the foregoing description of the system 10 is equally applicable to thesystem 310, except as noted below. Moreover, it will be appreciated uponreading and understanding the specification that aspects of the systems10, 310 may be substituted for one another or used in conjunction withone another where applicable.

Similarly to the system 10, the system 310 includes a shaft 314, atleast one extension arm 316 having a support for a medical device, and ahub 334 at a proximal end of the extension arm 316 and mounted to theshaft 314 for pivotable movement about a rotation axis A-A of the shaft314. The rotational control mechanism 340 of the system 310 includes atleast one floating stop 342 movably disposed in an elongated cavity 344of the hub 334, and which interacts with first and second contact faces346, 348 of the hub, and with first and second stop surfaces 350, 352fixed relative to the shaft 314, for providing the range of at least360-degrees rotation of the extension arm 316 about a rotation axis A-Aof the shaft 314.

As shown, the polyhedron shape of the floating stop 342 is in a wedgeshape such that first and second engagement surfaces 366, 368 of thefloating stop 342 compliment (with the same angles) the contact faces346, 348 forming the ends of the cavity 344 and/or the stop surfaces350, 352 forming opposite sides of the fixed stop 362. This enablesimproved contact area as the floating stop 342 moves between contactfaces 346, 348 during rotation of the hub 334 about the axis A-A, asdescribed in detail above.

Although the invention has been shown and described with respect to acertain embodiment or embodiments, it is obvious that equivalentalterations and modifications will occur to others skilled in the artupon the reading and understanding of this specification and the annexeddrawings. In particular regard to the various functions performed by theabove described elements (components, assemblies, devices, compositions,etc.), the terms (including a reference to a “means”) used to describesuch elements are intended to correspond, unless otherwise indicated, toany element which performs the specified function of the describedelement (i.e., that is functionally equivalent), even though notstructurally equivalent to the disclosed structure which performs thefunction in the herein illustrated exemplary embodiment or embodimentsof the invention. In addition, while a particular feature of theinvention may have been described above with respect to only one or moreof several illustrated embodiments, such feature may be combined withone or more other features of the other embodiments, as may be desiredand advantageous for any given or particular application.

What is claimed is:
 1. A medical device support system, comprising: ashaft; an extension arm having a support for a medical device; a hub ata proximal end of the extension arm and mounted to the shaft forpivotable movement of the extension arm and the hub about a rotationaxis of the shaft, the hub having an elongated cavity including firstand second contact faces; and at least one floating stop movablydisposed in the elongated cavity of the hub between the first and secondcontact faces; wherein the hub is pivotably mounted for a range of atleast 360-degrees rotation about the rotation axis, wherein the at least360-degrees rotation range is based on a compound of a first rotationrange and a second rotation range, wherein the first rotation range isdefined by a first movable amount of the at least one floating stopbetween first and second stop surfaces fixed relative to the shaft, andwherein the second rotation range is defined by a second movable amountof the at least one floating stop between the first and second contactfaces of the hub.
 2. The medical device support system of claim 1,wherein the at least one floating stop interfacing with one of the firstor second stop surfaces of the shaft and one of the first or secondcontact faces of the hub restricts rotation of the hub about therotation axis beyond the at least 360-degrees rotation range.
 3. Themedical device support system of claim 1, wherein the hub is pivotablymounted for the at least 360-degrees rotation from a first stop positionto a second stop position and vice versa, wherein at the first stopposition, the at least one floating stop interfaces with one of thefirst or second stop surfaces fixed relative to the shaft and one of thefirst or second contact faces of the hub to limit furthercounterclockwise rotation of the hub about the rotation axis, and at thesecond stop position, the at least one floating stop interfaces with anopposite one of the first or second stop surfaces and an opposite one ofthe first and second contact faces of the hub to limit further clockwiserotation of the hub about the rotation axis.
 4. The medical devicesupport system of claim 3, wherein the at least one floating stop issandwiched between the first stop surface and the first contact face atthe first stop position, and wherein the at least one floating stop issandwiched between the second stop surface and the second contact faceat the second stop position.
 5. The medical device support system ofclaim 1, wherein the first movable amount of the at least one floatingstop is determined by an amount of movement of the at least one floatingstop rotating at least partially about the rotation axis from a firststop position, in which the at least one floating stop engages both thefirst stop surface and the first contact face, to an intermediateposition, in which the at least one floating stop engages the secondstop surface, and wherein the second movable amount of the at least onefloating stop is determined by an amount of movement of the at least onefloating stop rotating at least partially about the rotation axis fromthe intermediate position to a second stop position, in which the atleast one floating stop engages both the second stop surface and thesecond contact face.
 6. The medical device support system of claim 5,wherein the second stop surface is configured to move the at least onefloating stop within the cavity from the intermediate position to thesecond stop position.
 7. The medical device support system of claim 1,wherein the first and second stop surfaces are formed by opposite sidesof at least one fixed stop radially outwardly protruding from an outersurface of the shaft, the at least one fixed stop being non-rotatableabout the rotation axis.
 8. The medical device support system of claim1, wherein the at least one floating stop includes a spherical ball. 9.The medical device support system of claim 1, wherein the elongatedcavity is formed by radially inwardly projecting surfaces of the hubthat at least partially enclose the at least one floating stop.
 10. Themedical device support system of claim 9, wherein the radially inwardlyprojecting surfaces of the hub form a radially inwardly projecting lug,and wherein the first and second contact faces of the hub form oppositeend portion surfaces of the lug.
 11. The medical device support systemof claim 1, wherein the first and second stop surfaces radially overlapwith the first and second contact faces of the hub, and radially overlapwith the at least one floating stop; and wherein the first and secondcontact faces include respective openings for receiving the first and/orsecond stop surfaces, thereby enabling the first or second stop surfaceto move the at least one floating stop within the elongated cavitybetween the first and second contact faces.
 12. The medical devicesupport system of claim 1, wherein the first and second stop surfacesradially overlap with opposite first and second engagement surfaces ofthe at least one floating stop, and wherein the first and second stopsurfaces and the opposite first and second engagement surfaces of the atleast one floating stop lie in the same plane that is perpendicular tothe rotation axis.
 13. The medical device support system of claim 1,wherein the first movable amount less than 360-degrees, and wherein thesecond movable amount is in a range from 1-degree to less than180-degrees.
 14. The medical device support system of claim 1, whereinthe at least 360-degrees rotation range is less than 540-degrees. 15.The medical device support system of claim 1, wherein the first andsecond stop surfaces are formed by opposite sides of a fixed stop, andwherein the shaft includes a plurality of receivers evenly spaced aboutthe rotation axis of the shaft for receiving the fixed stop.
 16. Themedical device support system of claim 1, wherein the shaft has an axialhollow and a radial aperture and wherein the cavity of the hub ispositioned to allow passage of electrical and communication linesthrough the axial hollow, through the radial aperture, and into alongitudinally extending cavity in the extension arm.
 17. The medicaldevice support system of claim 16, wherein the hub of the extension armincludes upper and lower pivot bearings configured to pivotably engagethe hub with the shaft, and a radial opening positioned axially betweenthe upper and lower pivot bearings, and wherein the cavity of the hub ispositioned to allow passage of the electrical and communication linesbetween the upper and lower pivot bearings, through the radial openingof the hub, and into the longitudinally extending cavity in theextension arm.
 18. A medical device support system, comprising: a shaft;an extension arm having a support for a medical device; a hub at aproximal end of the extension arm and mounted to the shaft for pivotablemovement of the extension arm and the hub about a rotation axis of theshaft, wherein the hub includes an elongated cavity having first andsecond contact faces; at least one floating stop disposed in the cavityand being movable between the first and second contact faces; and firstand second stop surfaces fixed relative to the shaft and radiallyextending to overlap with a rotation path of the at least one floatingstop; wherein the hub is pivotably mounted for a range of at least360-degrees rotation about the rotation axis from a first stop positionto a second stop position and vice versa, wherein at the first stopposition, the first stop surface engages a first engagement surface ofthe at least one floating stop and an opposite second engagement surfaceof the at least one floating stop engages the first contact face of thecavity, thereby limiting further counterclockwise rotation of the hubabout the rotation axis, and wherein at the second stop position, thesecond stop surface engages the second engagement surface of the atleast one floating stop and the opposite first engagement surface of theat least one floating stop engages the second contact face of thecavity, thereby limiting further clockwise rotation of the hub about therotation axis.
 19. The medical device support system of claim 18,wherein the at least one floating stop is configured to move with thehub about the rotation axis from the first stop position to anintermediate position between the first and second stop positions,wherein at the intermediate position the at least one floating stopengages with the second stop surface; and wherein the second stopsurface is configured to move the at least one floating stop within theelongated cavity from the intermediate position to the second stopposition.
 20. A method of rotating an extension arm about a shaft of amedical device support system, the extension arm having a support for amedical device and a hub at its proximal end mounted to the shaft forpivotable movement about a rotation axis of the shaft, the methodcomprising: rotating the hub over a range of at least 360-degrees aboutthe rotation axis, wherein the at least 360-degrees rotation range isbased on a compound of movement over a first rotation range and movementover a second rotation range, wherein movement over the first rotationrange includes moving at least one floating stop of the hub betweenfirst and second stop surfaces fixed relative to the shaft, and whereinmovement over the second rotation range includes moving the at least onefloating stop with the first or second stop surface between first andsecond contact faces of an elongated cavity of the hub.